Field
Aspects of the present invention generally relate to a technology of distinguishing whether a main subject is present in an input image.
Description of the Related Art
Various methods for detecting a main-subject area in an input image are known. Japanese Patent Laid-Open No. 2000-207564 discloses a method for determining a main-subject area based on the location or the size of a candidate object in an input image or based on semantic information indicating what a candidate area of a candidate object represents.
If such a main-subject area detection process is performed, for example, in an image capturing apparatus such as a digital camera, an autofocus (AF) adjustment and automatic tracking can be performed on a main subject.
Some input images, however, do not have a particular subject serving as a main subject. Examples of such images include an image (scenic image) of a distant view that includes the horizon, a skyline, or the like and that particularly does not have an attention-drawing object. Examples also include an image (uniform image) filled with a uniform texture such as an image filled with a wall or a stone wall. Such images do not have a particular main subject in many cases.
A method for detecting a main subject disclosed in Japanese Patent Laid-Open No. 2000-207564 detects at least one area as a main-subject area even in such an image having no particular main subject. This causes the AF, the automatic tracking, and other functions to be performed on an area that does not correspond to a main subject and causes a user to experience a feeling of uncertainty.